The present invention generally relates to an electronic timekeeping apparatus and, more particularly, relates to an electronic timekeeping apparatus with a dynamically changing liquid crystal display that allows electronically controlled color change of the liquid crystal display elements. Moreover, the present invention also allows electronic control of multi-colored liquid crystal display images, such images being generally independent of the time of day or alternatively provide a multi-colored indication of the time of day in an analog representation.
A wide variety of electronic timepieces utilizing liquid crystal display elements for time indication have been developed with great commercial success. Most of these electronic timepieces indicate the time in the form of numerals or in what is often referred to as a digital time display. More recently, the related art have fashioned liquid crystal displays for electronic watches that represent time in an analog or conventional type form.
Much of this related art in the field of electronic timekeeping devices with liquid crystal displays offers a variety of designs and configurations of the liquid crystal display elements that dynamically change to indicate the time-of-day. For example, U.S. Pat. No. 3,969,887 issued to Fukumoto (Jul. 20, 1976) shows an electronic timepiece composed of many liquid crystal display elements arranged in hour and minute indicating sections which are selectively activated in various display patterns so that the time is indicated in an analog form.
Another example is U.S. Pat. No. 4,212,159 issued to Nobel et al. (Jul. 15, 1980) which discloses an electronic timepiece with a liquid crystal display simulating a conventional mechanical analog timepiece. The liquid crystal material in Nobel et al. disclosure is activated in selected areas to change the appearance of the display to simulate movement of hands in an analog timepiece.
U.S. Pat. No. 4,213,294 issued to Freeman (Jul. 22, 1980) is one of many U.S. patents which disclose an electronic timepiece composed of many liquid crystal display elements that when activated simulate the positions of the hour and minute hands in an analog timepiece. Freeman utilizes 24 or 60 individual minute display elements shaped to combine with 12 or 24 hour display elements which are selectively activated to represent the indicated time in analog form.
Other related art includes U.S. Pat. No. 4,385,842 issued to Wiesner (May 31, 1983) which discloses an electronic watch which has a liquid crystal display that presents an analog indication of time in a conventional presentation of hour, minute and second hands that circulate around the watch face. Also, U.S. Pat. No. 4,435,046 issued to Nishimura (Mar. 6, 1984) that utilizes an analog display comprising conventional mechanical hour and minute hands together with a liquid crystal display wherein the activated segments of the liquid crystal display are isolated or separated from the analog display area.
Still other designs have introduced color changing schemes for providing indication of time as is shown in U.S. Pat. Nos. 4,647,217 (Mar. 3, 1987); and 4,707,141 (Nov. 17, 1987) both issued to Havel, which show variable color digital and analog timepieces, respectively. See also U.S. Pat. No. 5,228,013 issued to Bik (Jul. 13, 1993) which utilizes multiple liquid crystal display elements that change color to indicate time in a non-conventional form.
Many existing liquid crystal displays used in timepieces utilize conventional twisted-nematic (TN) displays that generally have a black on grey appearance. In addition, polarizing films, both external and reflective are typically incorporated within such devices which tends to diminish the brightness of the display and limit the viewing angles at which the display is clearly visible. Color appearance of the liquid crystal display is introduced through the use of colored filters, colored background lighting, and the like. However, when the appearance of color is incorporated with such timekeeping devices, the colors are often preselected and static.
The above-described and related references typically employ liquid crystal displays that include static background display elements coupled with active or dynamic time indicating display elements. As such, the aesthetic presentation of the liquid crystal display is limited by the functional aspect of the device.
More recent advancements in liquid crystal displays have disclosed the use of guest dyes within the liquid crystal material to provide color modulation. See for example, U.S. Pat. No. 5,289,301 issued to inventor-applicant Donald Brewer (Feb. 22, 1994) which suggests the broad concept of using color modulation liquid crystal displays in a wristwatch in some non-enabled manner.